include package names in "of type 'Apple' to 'Apple'" error messages

[jrfondren]

Consider the following program:

package main

import "core:fmt"
import "core:bytes"

Buffer :: struct {}

main :: proc() {
	b1 : [^]bytes.Buffer = &bytes.Buffer{}
	b2 := Buffer{}
	p1 : [^]Buffer = &b2
	b1 = p1
}

This fails to compile with this error message:

Cannot assign value 'p1' of type '[^]Buffer' to '[^]Buffer' in assignment

Here it's clear what the problem is, but it's frequently not clear, and has come up in beginner discussions where a custom Buffer was accidentally passed to a procedure expecting a Vulkan Buffer, and instead of the error message immediately revealing that problem, it looked like a problem the programmer's understanding of pointers, or like a bug in the language.

Alternatives

Cannot assign value 'p1' of type '[^]Buffer (main)' to '[^]Buffer (bytes)' in assignment

Cannot assign value 'p1' of type '[^]main.Buffer' to '[^]bytes.Buffer' in assignment

To always include the package information might just make for noisier error messages, but it should definitely be included when it would disambiguate types like this.

Prior references

This came up and was mentioned as a specific enhancement to be made in #83 , but there was a more serious bug going on with that issue as the packages in an improved error message would've been the same.

[Kelimion]

It would only need to add the package. prefix or (package) suffix if the type names are otherwise identical. That would avoid the noise.